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Convert tons of refrigeration to BTU per hour instantly. Whether you're sizing an HVAC system, estimating cooling capacity, or comparing air conditioning units, this free calculator provides accurate tons-to-BTU conversions using the standard factor of 12,000 BTU/hr per ton.
tons
Formula: 1 Ton of Refrigeration = 12,000 BTU/hr
Multiply tons by 12,000 to get BTU/hr, or divide BTU/hr by 12,000 to get tons.
Below is a reference table showing common tonnage values and their equivalent BTU per hour ratings, along with typical real-world applications for each capacity level.
| Tons (Refrigeration) | BTU/hr | Typical Application |
|---|---|---|
| 0.5 tons | 6,000 BTU/hr | Window AC unit, small room |
| 1 ton | 12,000 BTU/hr | Single-room portable AC |
| 1.5 tons | 18,000 BTU/hr | Large room or small apartment |
| 2 tons | 24,000 BTU/hr | Small house or large apartment |
| 2.5 tons | 30,000 BTU/hr | Medium apartment or condo |
| 3 tons | 36,000 BTU/hr | Average-sized home (1,500 sq ft) |
| 3.5 tons | 42,000 BTU/hr | Mid-sized home (1,750 sq ft) |
| 4 tons | 48,000 BTU/hr | Larger home (2,000 sq ft) |
| 5 tons | 60,000 BTU/hr | Large home (2,500 sq ft) |
| 7.5 tons | 90,000 BTU/hr | Small commercial space |
| 10 tons | 120,000 BTU/hr | Small office building |
| 15 tons | 180,000 BTU/hr | Medium commercial building |
| 20 tons | 240,000 BTU/hr | Large commercial building |
| 25 tons | 300,000 BTU/hr | Large retail or restaurant |
| 30 tons | 360,000 BTU/hr | Warehouse or industrial space |
| 50 tons | 600,000 BTU/hr | Large industrial facility |
| 100 tons | 1,200,000 BTU/hr | Major commercial complex |
A ton of refrigeration is a unit of power used to describe the heat-absorption capacity of cooling and air conditioning systems. It is defined as the rate of heat transfer required to melt one short ton (2,000 pounds) of ice at 32°F (0°C) over a 24-hour period. Since the latent heat of fusion for ice is 144 BTU per pound, the total energy required is 2,000 × 144 = 288,000 BTU per day. Dividing by 24 hours gives the familiar figure of 12,000 BTU per hour.
The term dates back to the late 19th century when commercial ice production was the primary method of cooling buildings and preserving food. Before mechanical refrigeration, businesses purchased ice by the ton, so engineers naturally described cooling systems in terms of how many tons of ice they could replace. Even though modern HVAC systems use refrigerant cycles rather than ice, the ton of refrigeration remains the standard unit for rating cooling capacity in the United States.
The British Thermal Unit (BTU) itself is defined as the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit. When paired with the time component (per hour), BTU/hr measures the rate of thermal energy transfer, which is why cooling and heating systems use this metric. Understanding the relationship between tons of refrigeration and BTU/hr is essential for anyone involved in HVAC system selection, building energy analysis, or mechanical engineering.
BTU/hr = Tons × 12,000
To convert back: Tons = BTU/hr ÷ 12,000
This is a common size for homes between 1,200 and 1,800 square feet.
Typical for medium-sized offices, restaurants, or retail stores.
A 4-ton system is suitable for homes around 2,000 square feet.
To quickly estimate BTU/hr from tons, multiply by 12 and add three zeros. For example, 5 tons: 5 × 12 = 60, then add three zeros = 60,000 BTU/hr. Going the other direction, remove three zeros and divide by 12: 36,000 becomes 36 ÷ 12 = 3 tons.
| Home Size (sq ft) | Recommended Tons | BTU/hr Required |
|---|---|---|
| 600 - 900 | 1.5 | 18,000 |
| 900 - 1,200 | 2 | 24,000 |
| 1,200 - 1,500 | 2.5 | 30,000 |
| 1,500 - 1,800 | 3 | 36,000 |
| 1,800 - 2,100 | 3.5 | 42,000 |
| 2,100 - 2,400 | 4 | 48,000 |
| 2,400 - 3,000 | 5 | 60,000 |
| Building Type | Typical Tons | BTU/hr Range |
|---|---|---|
| Small retail store | 5 - 10 | 60,000 - 120,000 |
| Restaurant | 10 - 25 | 120,000 - 300,000 |
| Office building | 20 - 50 | 240,000 - 600,000 |
| Hotel | 50 - 200 | 600,000 - 2,400,000 |
| Hospital | 100 - 500 | 1,200,000 - 6,000,000 |
| Data center | 50 - 1,000+ | 600,000 - 12,000,000+ |
| Tons | BTU/hr | kW (Thermal) | kcal/hr |
|---|---|---|---|
| 1 | 12,000 | 3.517 | 3,024 |
| 2 | 24,000 | 7.034 | 6,048 |
| 3 | 36,000 | 10.551 | 9,072 |
| 5 | 60,000 | 17.585 | 15,120 |
| 10 | 120,000 | 35.170 | 30,240 |
| 20 | 240,000 | 70.340 | 60,480 |
| 50 | 600,000 | 175.850 | 151,200 |
An undersized AC system runs constantly and cannot maintain comfortable temperatures. An oversized system short-cycles, wasting energy and causing humidity problems. Converting between tons and BTU/hr ensures you select the correct equipment capacity for your space.
Knowing the BTU/hr output of your cooling system allows you to estimate electrical consumption and operating costs. Combined with the equipment's EER or SEER rating, you can calculate monthly electricity costs and compare the efficiency of different units.
Different manufacturers may list cooling capacity in tons, BTU/hr, or kilowatts. Being able to convert between these units lets you compare products on equal footing, ensuring you get the best value and performance for your specific needs.
HVAC engineers, contractors, and building designers use tons-to-BTU conversions daily for load calculations, ductwork sizing, and system design. Accurate conversions are critical for meeting building codes and ensuring occupant comfort.
A ton of refrigeration equals 12,000 BTU per hour, not 12,000 BTU total. The per-hour distinction is crucial because cooling capacity is measured as a rate. Over 24 hours, one ton actually absorbs 288,000 BTU.
A refrigeration ton is a measure of cooling power, not weight. It should not be confused with a short ton (2,000 lb), long ton (2,240 lb), or metric ton (1,000 kg). Always verify which type of "ton" is being discussed.
The tons-to-BTU conversion gives you the theoretical cooling capacity. In practice, factors like ductwork losses, insulation quality, climate zone, sun exposure, and occupancy loads all affect how much capacity you actually need. Professional HVAC load calculations (Manual J) account for these variables.
When estimating electricity costs from BTU/hr ratings, use SEER (Seasonal Energy Efficiency Ratio) for seasonal averages and EER for peak load conditions. Modern units typically range from 14 to 25 SEER, meaning efficiency varies significantly between models.
Part of an AC system's BTU capacity goes toward removing moisture (latent cooling) rather than lowering temperature (sensible cooling). In humid climates, you may need more BTU/hr than the square footage alone suggests because the system must handle a greater dehumidification load.
Oversizing an air conditioning system leads to short cycling, where the unit turns on and off frequently. This increases wear on components, raises energy bills, and prevents proper dehumidification. Always size based on a proper load calculation rather than rounding up.
One ton of refrigeration equals exactly 12,000 BTU per hour. This standard conversion factor is used throughout the HVAC industry to size air conditioning and refrigeration equipment.
The term originates from the amount of heat needed to melt one short ton (2,000 pounds) of ice at 32 degrees Fahrenheit over a 24-hour period. Melting that much ice absorbs 288,000 BTU per day, which equals 12,000 BTU per hour.
BTU (British Thermal Unit) is a measure of energy, while BTU/hr (BTU per hour) is a measure of power or rate of energy transfer. When converting tons of refrigeration, the result is always in BTU/hr because a ton measures cooling capacity, which is a rate.
A general rule of thumb is 1 ton of cooling per 500 to 600 square feet. For a 2,000 square foot house, you would typically need a 3.5 to 4 ton air conditioning system, which equals 42,000 to 48,000 BTU/hr. Exact sizing depends on climate, insulation, and sun exposure.
Yes. While the ton of refrigeration is traditionally used for cooling, the BTU/hr conversion (1 ton = 12,000 BTU/hr) applies equally to heating load calculations. Furnaces and heat pumps are commonly rated in BTU/hr, making this conversion useful for comparing heating and cooling capacities.
One ton of refrigeration equals approximately 3.517 kilowatts (kW). To convert, multiply the number of tons by 3.517. For example, a 5-ton system equals about 17.58 kW of cooling capacity.
The Energy Efficiency Ratio (EER) measures how many BTU/hr of cooling an air conditioner produces per watt of electricity consumed. A higher EER means greater efficiency. To find the electrical draw of a system, divide the total BTU/hr output by the EER rating.
No, they are completely different units. A metric ton is a unit of mass equal to 1,000 kilograms. A ton of refrigeration is a unit of cooling capacity equal to 12,000 BTU/hr. The refrigeration ton is based on the short ton (2,000 pounds) used in the ice trade, not the metric system.
Multiply the room area in square feet by 20 BTU for a rough estimate. For a 300 square foot room, you would need approximately 6,000 BTU/hr, or about 0.5 tons of cooling. Adjust upward for sunny rooms, kitchens, or high ceilings.
Commercial buildings typically require 1 ton of cooling per 400 to 500 square feet due to higher occupancy and equipment heat loads. A 10,000 square foot office may need a 20 to 25 ton system, which equals 240,000 to 300,000 BTU/hr of cooling capacity.
Disclaimer: This calculator is provided for informational and educational purposes only. While we strive for accuracy, always consult a licensed HVAC professional for system sizing and installation decisions. Actual cooling requirements depend on climate, insulation, building orientation, occupancy, and other factors not accounted for by a simple conversion.